selinux: fix overflow and 0 length allocations

Throughout the SELinux LSM, values taken from sepolicy are
used in places where length == 0 or length == <saturated>
matter, find and fix these.

Signed-off-by: William Roberts <william.c.roberts@intel.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

2 files changed, 5 insertions, 0 deletions

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index 456e1a9bcfde..34afeadd9e73 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -242,6 +242,8 @@ int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
                 goto err;
 
         len = le32_to_cpu(buf[2]);
+        if (((len == 0) || (len == (u32)-1)))
+                goto err;
 
         rc = -ENOMEM;
         key = kmalloc(len + 1, GFP_KERNEL);
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 4b243855ed7b..8c661f0451ec 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1094,6 +1094,9 @@ static int str_read(char **strp, gfp_t flags, void *fp, u32 len)
         int rc;
         char *str;
 
+        if ((len == 0) || (len == (u32)-1))
+                return -EINVAL;
+
         str = kmalloc(len + 1, flags);
         if (!str)
                 return -ENOMEM;